全文获取类型
收费全文 | 6143篇 |
免费 | 487篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 58篇 |
综合类 | 9篇 |
化学工业 | 2560篇 |
金属工艺 | 78篇 |
机械仪表 | 86篇 |
建筑科学 | 268篇 |
矿业工程 | 34篇 |
能源动力 | 161篇 |
轻工业 | 1138篇 |
水利工程 | 41篇 |
石油天然气 | 35篇 |
无线电 | 259篇 |
一般工业技术 | 940篇 |
冶金工业 | 327篇 |
原子能技术 | 16篇 |
自动化技术 | 631篇 |
出版年
2024年 | 12篇 |
2023年 | 59篇 |
2022年 | 444篇 |
2021年 | 773篇 |
2020年 | 230篇 |
2019年 | 210篇 |
2018年 | 255篇 |
2017年 | 207篇 |
2016年 | 264篇 |
2015年 | 224篇 |
2014年 | 273篇 |
2013年 | 449篇 |
2012年 | 376篇 |
2011年 | 412篇 |
2010年 | 278篇 |
2009年 | 276篇 |
2008年 | 277篇 |
2007年 | 243篇 |
2006年 | 218篇 |
2005年 | 155篇 |
2004年 | 142篇 |
2003年 | 117篇 |
2002年 | 100篇 |
2001年 | 55篇 |
2000年 | 46篇 |
1999年 | 57篇 |
1998年 | 38篇 |
1997年 | 43篇 |
1996年 | 43篇 |
1995年 | 35篇 |
1994年 | 38篇 |
1993年 | 31篇 |
1992年 | 27篇 |
1991年 | 16篇 |
1990年 | 24篇 |
1989年 | 11篇 |
1988年 | 18篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 18篇 |
1984年 | 16篇 |
1983年 | 18篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1974年 | 5篇 |
1966年 | 5篇 |
排序方式: 共有6641条查询结果,搜索用时 593 毫秒
111.
Iosif Vranakis Anastasia Papadioti Yannis Tselentis Anna Psaroulaki Georgios Tsiotis 《Proteomics. Clinical applications》2013,7(1-2):193-204
Coxiella burnetii, the causative agent of Q fever, is an intracellular bacterium and a potential weapon for bioterrorism. The widespread throughout the world, zoonosis is manifested clinically as a self-limited febrile illness, as pneumonia (acute Q fever) or as a chronic illness with endocarditis being its major complication. The recent Netherlands Q fever outbreak has driven the bacterium from a relatively cryptic, underappreciated, “niche” microorganism on the sideline of bacteriology, to one of possibly great impact on public health. Advances in the study of this microorganism proceeded slowly, primarily due to the, until recently, obligatory intracellular nature of the pathogen that in its virulent phase I must be manipulated under biosafety level-3 conditions. Proteomic studies, in particular, have generated a vast amount of information concerning several aspects of the bacterium such as virulence factors, detection/diagnostic and immunogenic biomarkers, inter-/intraspecies variation, resistance to antibiotics, and secreted effector proteins with significant clinical impact. The phenomenon observed following the genomics era, that of generation and accumulation of huge amount of data that ultimately end up unexploited on several databases, begins to emerge in the proteomics field as well. This review will focus on the advances in the field of C. burnetii proteomics through MS, attempting in parallel to utilize some of the proteomics findings by suggesting future directions for the improvement of Q fever diagnosis and therapy. 相似文献
112.
Clausen CH Dimaki M Panagos SP Kasotakis E Mitraki A Svendsen WE Castillo-León J 《Scanning》2011,33(4):201-207
In this report electrostatic force microscopy (EFM) is used to study different peptide self-assembled structures such as tubes and particles. It is shown that not only geometrical information can be obtained using EFM, but also information about the composition of different structures. In particular we use EFM to investigate the structures of diphenylalanine peptide tubes, particles, and CSGAITIG peptide particles placed on pre-fabricated SiO(2) surfaces with a backgate. We show that the cavity in the peptide tubes could be due to the presence of water residues. Additionally we show that self-assembled amyloid peptides form spherical solid structures containing the same self-assembled peptide in its interior. In both cases transmission electron microscopy is used to verify these structures. Further, the limitations of the EFM technique are discussed, especially when the observed structures become small compared with the radius of the AFM tip used. Finally, an agreement between the detected signal and the structure of the hollow peptide tubes is demonstrated. 相似文献
113.
Binfeng Li Keming Zhu Anna Wu Xiaolong Zhang 《International journal of human-computer interaction》2013,29(3):169-177
Global Positioning System (GPS) is currently the most often used wayfinding aid for driving. Yet GPS is originally designed to provide a driving guide rather than to help users gain spatial knowledge. Accordingly, GPS might be less usable in situations where spatial knowledge is required. This study experimentally compared two wayfinding aids using simulated driving tasks in a virtual environment: a simulated GPS and a dual-scale exploration aid (DSEA). The DSEA, which provides two levels of details—both detailed and contextual information—was proposed to support participants in finding and selecting routes by themselves. The results show that although DSEA was less helpful in leading participants to their destination and corresponded to more turning errors in simulated driving, it was more useful for the corresponding participants to establish spatial awareness and a cognitive map. The influence of participants' spatial ability test score on wayfinding performance was measured and discussed. The proposed DSEA design and experimental results show some indications for designing new wayfinding aids aimed at reducing wayfinding errors and constructing cognitive maps while still providing easy navigation. 相似文献
114.
Gravel constitutes the filter medium in subsurface flow constructed wetlands (SSF CWs) and its porosity and hydraulic conductivity decrease over time (clogging), limiting the lifespan of the systems. Using gravel of poor quality accelerates clogging in wetlands. In this study, gravel samples from six different wetland systems were compared with regards to their mineral composition and mechanical resistance properties. Results showed that both mineralogy and texture are related to mechanical resistance. Accordingly, gravel with high content of quartz (> 80%) showed a lower percentage of broken particles (0.18-1.03%) than those with lower content of quartz (2.42-4.56% media broken). Although granite is formed by high durability minerals, its non-uniform texture results in a lower resistance to abrasion (ca. 10% less resistance than calcareous gravel). Therefore, it is recommended to use gravels composed mainly of quartz or, when it is not available, limestone gravels (rounded and uniform) are recommended instead. The resistance to abrasion (LAA test) seems to be a good indicator to determine the mechanical properties of gravels used in CWs. It is recommended to use gravels with LAA below 30% in order to avoid a rapid clogging due to gravel crumbling and subsequent mineral solids accumulation. 相似文献
115.
116.
117.
Anna Bucalo 《Journal of Logic, Language and Information》1994,3(3):211-232
We present a semantic study of a family of modal intuitionistic linear systems, providing various logics with both an algebraic semantics and a relational semantics, to obtain completeness results. We call modality a unary operator on formulas which satisfies only one rale (regularity), and we consider any subsetW of a list of axioms which defines the exponential of course of linear logic. We define an algebraic semantics by interpreting the modality as a unary operation on an IL-algebra. Then we introduce a relational semantics based on pretopologies with an additional binary relationr between information states. The interpretation of is defined in a suitable way, which differs from the traditional one in classical modal logic. We prove that such models provide a complete semantics for our minimal modal system, as well as, by requiring the suitable conditions onr (in the spirit of correspondence theory), for any of its extensions axiomatized by any subsetW as above. We also prove an embedding theorem for modal IL-algebras into complete ones and, after introducing the notion of general frame, we apply it to obtain a duality between general frames and modal IL-algebras. 相似文献
118.
Computational Visual Media - Accurate and temporally consistent modeling of human bodies is essential for a wide range of applications, including character animation, understanding human social... 相似文献
119.
Anna Medyńska Danuta Zwolińska Ryszard Grenda Monika Miklaszewska Maria Szczepańska Agnieszka Urzykowska Katarzyna Zachwieja Katarzyna Kiliś‐Pstrusińska 《Hemodialysis international. International Symposium on Home Hemodialysis》2017,21(4):557-565
Introduction: The aim of this study was to analyze the selected psychosocial aspects of chronic kidney disease in children treated with hemodialysis (HD). Methods: The study included 25 children treated with HD aged 2 to 18 years and their parents. Data concerning the illness and socio‐demographic parameters was collected. We used the Paediatric Quality of Life Inventory (PedsQL) for patients and for their parents the PedsQL‐proxy version, General Health Questionnaire (GHQ‐12), Berlin Social Support Scales (BSSS), and the Caregivers Burden Scale (CBS) to evaluate health‐related quality of life (QoL) of HD children and their primary caregivers. Findings: In the PedsQL test, the QoL of HD children was lower than in healthy children. Children treated with HD assessed their QoL on the PedsQL questionnaire higher than the primary caregivers, on all subscales as well as an overall health‐related QoL. Scoring below 2 on the GHQ‐12 test was reported in 56% of mothers, which may indicate that psychological symptoms have intensified. There was no correlation between BSSS, CBS, and GHQ‐12. Discussion: The assessment of QoL in pediatric patients would allow for the earliest possible identification of their nonsomatic problems and irregularities. This could, consequently, contribute to improving QoL in both children with chronic kidney disease and their families. 相似文献
120.